positron-positron collision

См. также в других словарях:

• Positron — Propriétés générales Classification Lepton Composition élémentaire Propriétés physiques Masse 510,998 918 (44) keV.c 2 (9,109 382 6(16)×10 31 kg) Charge électrique +1,602 …   Wikipédia en Français

• positron-emission tomography — n tomography in which an in vivo, noninvasive, cross sectional image of regional metabolism is obtained by a usu. color coded cathode ray tube representation of the distribution of gamma radiation given off in the collision of electrons in cells… …   Medical dictionary

• positron emission tomography — (PET, positron emission computed tomography, PECT) a technique in nuclear medicine for cross sectional imaging that enables a noninvasive assessment and localization of metabolic activity to be made. Emission of a positron by a radioisotope… …   Medical dictionary

• positron emission — a form of radioactive decay in which a positron (β+) and neutrino are ejected from the nucleus as a proton is transformed into a neutron. Collision of the positron with an electron causes annihilation of both particles and conversion of… …   Medical dictionary

• positron emission tomographypositron emission comp — PET; = PECT a technique in nuclear medicine for cross sectional imaging that enables a noninvasive assessment and localization of metabolic activity to be made. Originally used to study activity in the brain, PET is now also used for… …   The new mediacal dictionary

• positron-emission tomography — noun Date: 1976 tomography in which a cross sectional image of regional metabolism is obtained by a usually color coded representation of the distribution of gamma radiation given off in the collision of electrons in cells with positrons emitted… …   New Collegiate Dictionary

• positron-emission tomography — ¦ ̷ ̷  ̷ ̷ ˌ ̷ ̷  ̷ ̷ ¦ ̷ ̷  ̷ ̷ noun : tomography in which an in vivo, noninvasive, cross sectional image of regional metabolism is obtained by a usually color coded video representation of the distribution of gamma radiation given off in the… …   Useful english dictionary

• Electron-positron annihilation — occurs when an electron and a positron (the electron s anti particle) collide. The result of the collision is the conversion of the electron and positron and the creation of gamma ray photons or, less often, other particles. The process must… …   Wikipedia

• Large Electron-Positron Collider — The Large Electron Positron Collider (LEP) was one of the largest particle accelerators ever constructed.It was built at CERN, a multi national center for research in nuclear and particle physics near Geneva, Switzerland. LEP was a circular… …   Wikipedia

• Large Electron–Positron Collider — LEP redirects here. For other uses, see LEP (disambiguation). The former LEP tunnel at CERN being filled with magnets for the LHC The Large Electron–Positron Collider (LEP) was one of the largest particle accelerators ever constructed. It was… …   Wikipedia

• Grand collisionneur électron-positron — Grand collisionneur électron positon Le grand collisionneur électron positon, ou LEP (de l anglais Large Electron Positron collider) était un accélérateur de particules circulaire de 27 km de circonférence, passant sous le site du CERN entre la… …   Wikipédia en Français